The global One Health index (GOHI) is a comprehensive measure developed to assess the integrated approach to human, animal, and environmental health. The construction of GOHI involves five steps: (i) framework formulation, (ii) indicator selection, (iii) database building, (iv) weight determination, and (v) GOHI score calculation. To ensure its reliability, a GOHI expert advisory committee was established, drawing expertise from diverse fields such as human medicine, veterinary science, and environmental science. The foundational principles of GOHI are based on the interconnectedness of human, animal, and environmental health, the holistic perspective required to address global health challenges, and the promotion of coordinated development within these systems. The GOHI framework consists of three layers: external drivers index (EDI) assessing factors influencing One Health’s evolution, intrinsic drivers index (IDI) evaluating practices across human, animal, and environmental interfaces, and core drivers index (CDI) measuring the management of key scientific areas, such as zoonotic diseases, antimicrobial resistance, food security, climate change, and governance, etc. Indicator selection was guided by expert consultations and literature reviews, ensuring they are relevant, accessible, and globally comparable. The fuzzy analytical hierarchy process (FAHP) was used to assign weights to the indicators, and scores were normalized using specific equations to derive the overall GOHI score. The GOHI serves as a pivotal tool for global health evaluation, promoting a more integrated approach to address health challenges.